Indicating system



July 5, 1932. I C STEWART 1,866,327

INDICATING SYSTEM Filed Aug. 16, 1929 Remote or Super-visor-y Control Equipment Inventor:

Clyde E. Stewart,

l-lis Atnorneg.

Patented July 5, 1932 UNITED STATES PATENT OFF-ICE CLYDE E. STEWART, OF DREXEL HILL, PENNSYLVANIA, ASSIGNOR TO GENERAL ELEG- IERIG COMPANY, A CORPORATION OF NEW YORK k rnnrcarrne svs'rmvi Application filed August 16, 1929. Serial No. 385,459.

My present invention relates to remote indicating systems and more particularly to improvements in means for remotely indicating the position of apparatus units which are operable to three or more positions.

Means have been proposed in the prior art for transmitting from a remote point to an operators station a number of impulses of equal duration corresponding to the position of a water gate, for example, or other element the position of which is to be indicated. Where the position of an element which is operable to a large number of positions is to be indicated the number of impulses transmitted by means of the type indicated is'such that the counting of the impulses by the operator becomes tiresome and annoying and the likelihood of error is great.

One of the objects of my invention is to provide means whereby a code of impulses may be transmitted to the operators station corresponding to the position of the desired movable element, the code comprising a number of long and short impulses proportioned in accordance with the displacement of the element from'a predetermined reference point. Thus, for example, in accordance with my invention means are provided whereby when the element is displaced from a predetermined reference point by a number of whole units a corresponding number of long impulses will be transmitted indicating the position of the element with reference to said point. If the displacement of the element is less than a whole unit a number of short impulses will be transmitted corresponding to the number of fractions of a unit of displacement of said element from the reference point. Further, if the displacement be greater than 40 one or more whole units by certain fractions of a unit a number of long impulses will be transmitted corresponding to the number of whole units of displacement and also a number of short impulses corresponding to the additional fractions of a unit of displacement of the element from the reference point. 1

Thus the long and short impulses are proportioned in code in accordance with the position of the movable element. 7 Another object of the invention is to provide means whereby the position ofa unit which is operable to three-or more positions may be determined from a remote point which are comparatively simple in circuit arrangement and which may be economically constructed and employed in connection with remote control and supervisory systems of types now well known'in the art.

The novel features which'I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing in which the single figure represents an embodiment of my invention. p

Referring to the drawing I have shown at 16 a movable element which is arranged for 'slidable engagement upon a vertical support ing' member 17. This element may in itself constitute a member, the position of which is to be indicated at a remote point, or the element may be movable dependently'upon some other variable the position, or condition, of which is to be remotely indicated. I have shown the member 16 as being connected, by means of a cable 18', with a float 19 which may vary in position, for example, depending upon the height of water at a dam, or density of liquid in a tank, which height, or density, is to be remotely indicated at the remote point. v

Disposed along the pathof movement of the element 16 are a plurality of stationary contacts indicated at 1, 2, 3-15 each of which has cooperating"therewith a movable contact 1, 2, 315. Eachof these movable contacts is pivotallysupported atthe leftend, as shown in the drawing, and the right end thereof is arranged tofoscillate about this support between the cooperating sta tionary contact and a lower stop 1", 2", 315. The right end of each of the movable contacts is forked and is so positioned with reference to the member 16 that as the member 16 travels in its path past any of the oscillating movable contacts it-engages the foremost tine of the fork and carries the fork with it over center, and into engagement either with the stationary contact or the stop, in which position the movable contact is re- 5 tained by a suitable biasing spring.

Thusfor example .as the member 16 moves upwardi-in .its pathit engages theupper. tines of the respective forked contacts as it passes and carries them upward into engagement tained by their biasing-springs In its down-v ward movement the member 16 engages the lower tines of the movable contacts and carries them out from engagement with their stae tionary contacts and causes them to rest upon the corresponding stop. I

Thesignaltransmitter, WhichI employ in connection. with my system, comprises. an

oscillation. generator in the formof an.in--

duction coil20 having a secondary winding 21 and-aprimary winding 21f whichis cone nected. in. circuit. with the. usual interrupter contact. The; output .from the generatormaybee supplied. through a suitable supervisory 2 control. system 37 tov a supervision. station.

Thisoscillation generator is arranged to. be;

controlled by means; of the. lower wipers 23 and 24=of a-rotary switching device. 22.

The: switching device comprises. an- 0rdi- No. 1,472,465 to O. Forsberget al., issued October 30,. 1.923.. As; shown, the selector. switch comprises four single .ended wipers 23, 24, 25; and. 26 andtheir cooperatingbanks of contacts 23. 24, 25 and 26. Thelower two.

their cooperating relays. 27. and.28, act asia motor continuously to. rotate. the different wipersstep by step.-

451 Thee wipers 23. and24extend.inopposite directions; and. alternately engage. their respective banks-ofcontacts. These wipers are connected in circuit withtheprimarywind. ingofinduction C011 20, whichcircnit includesv in the different positions of the respective wipers. 23- and 24,. the contact 1 2., 3 etc.

depending upon the-number ofthese contacts which have been operated to their upper position bymovement ofithe-member. 16.. Inthisi way anumberofiimpulses may be tranimitted.

depending, upon. the: position of the. meme ber. 16.

Having now generally indicatedthe.characr terofthee equipment to be. described a better understanding may be had by reference to its operation.

The switch. 22 may be set into operation by energization of the'winding of. relay 36,

whichzwi'ndingmay beenergizedthrough the remote control or. supervisory equipment;37.

with. their upper contactswhere they are re nary selector switchwhich. is: well. known inthe. art, one type; of whichis shown inPatent:

Upon energization of this relay a circuit is completed which extends from the positive side of the source of potential 32 through the contacts of relay 36, normal contact of the bank 26 and wiper -26, interrupter con- 1v tactsofmotor magnet 27, winding of relay 28, to thenegativeside ofthesourceof potential. Operation of relay 28 completes an obvious circuit for motor magnet 27, which magnet upon operation of'its interrupter contacts deenergizes. relay 2-8, which in turn deenergizes the motor magnet. The motor magnet then advancesi all of the wipers on to their next bank contact. All of the remaining contacts ofthe bank 25 and 26 are connected together and are :connected. to thepositivesideof bat tery 32. such that when .the wiper 26 engages its first off-normal contact the. relay 28 again becomesienergizcd and'the cycle. of. operation of relay 28 and motor magnet. 27 repeats it self, thereby continuously advancing the wipers of the selector switchstep by step over their banks of contacts at a rate determined by the relay 28. This relay is preferably of the slow acting.- typewhereby the operation of thesystem-is rendered sufficiently slow to avoid. confusion. ofithe. signals at the remote point.

If we assume that the-member 16 isinthe position shown in the drawing it will be seen that the circuit of; the primary winding of induction coil 20. is. completed upon the 1st, 2nd, 3rd, 4th, 5th and 6th contacts, all of which are included in a group A in the bank 24, the: circuit throughthe 1st, 3rd and 5th. 100 off-normalv contacts. extending respectively through contacts: 1, 1.; 2, 2.; 3, 3 and the circuit throughthe.intermediate contacts extending-through the left hand contact and armature. of relay 33 and contacts 4, 4.. Thus asthe wiper 24'passes the first six con tacts ofgroupA the induction. coil will be continuously-energized andwill cause a relatively long, continuous high frequency impulse to. be transmitted through the super- 11o visory system 3.7' to. the remote-point. The group ofcontacts-A is spaced apart fromthe group. B sufliciently to permit the first and second. groups of impulses of the transmitted code to be distinguished. The group of contacts B andthe associated relay 34- are con.- nected to contacts 6, 6; 7, 7; 8,8; 9, 9; and 10, 10 in the same way as the first group and its associated relay 33. are connected to the contacts 1, 15, 5.. However since'the contacts 9 and 10 are in the lower position and relay 34 is deenergized thecircuit is only completed through the 1st, 8rd and 5th contacts of group B, the circuit of the intermediate contacts being interrupted at the left 1 handcontact of deenergized relay 34. Thus as the Wiper 24 rotates over this group of contacts three short impulses of high frequency current will be transmitted.

Theqgroupvof. contacts Cv areconnected in a similar manner to the contacts 11, 11; 12, 12; 13, 13; 14, 14; and 15, 15, but since all of the contacts 11 to 15' are in their lower osition the high frequency generator will e deenergized when the wipers 23 and 24: engage with the contacts of group C. Accordingly the code transmitted upon each complete revolution of the rotary switching device will comprise a long high frequency impulse followed by three short high frequency impulses indicating that the member 16 is in a position corresponding to contact 8 and that the water in the dam is at a corresponding height.

Let us assume now that the member 16 is moved upwardly sufiiciently to operate contact 10 into engagement with its stationary contact, but not sufiicient to operate the contact 11'. An obvious circuit will then be completed for relay causing this relayto operate and thereby connect each of the intermediate contacts in the group B through the left hand cont-act and armature of relay 34 and contact 9 and its stationary contact to the positive side of the battery. 'At the same time it interrupts the connection of the last contact of the group 13. Thus as the wiper 24 now passes over the bank 24 a relatively long continuous high frequency impulse will be transmitted and the code transmitted during each revolution of the switching device 25 will comprise two long impulses. As the member now moves upwardly sufficiently to operate contact 14' against its stationary contact 14 the'code transmitted during each revolution of the switch 25 will be two relatively long high frequency impulses and four relatively short high frequency impulses, thereby indicating this position of the member 16.

It will be seen that if a greater number of positions of the member 16 are to be indicated further movable contacts 1, 2, etc., may be provided and connected to additional groups of contacts in the bank 23.

Since these switches are ordinarily constructed with 25 contacts in each bank it will be seen that as many as 25 positions may be indicated with a single switch employing the whole of two banks of contacts as already described. By slightly modifying the circuit additional selectors can be added to obtain a larger number of positions.

It will thus be seen that the position of the member 19 may be readily determined by means of the code. For example, it may be assumed that a long impulse represents a certain unit of displacement, as for example I 10 feet, of the member 16 from the base of the supporting member 17, and each of the short impulses'representsa certain fraction of said unit, as for example 2 feet. Thus the height of water can be readily indicated by 1 the code and with much greater facility than would be the case if it -.were necessary for the operator to .listen'rto a long series of short impulses, each of which corresponds to a fraction ofaunit of displacement as for example in the case assumed 2 feet.

-At the point where indications are tobe made any suitable receiving device, not shown, may be employed to respond to'the received high frequency impulses, as for example an ordinary telephone receiver, in I duction howler orloud speaker.

While I have shown a particular embodiment'of my invention it will, of course, be understood that I do not wish to be limited thereto since many modifications both to the circuit arrangement and instrumentalities employed may be made and I therefore contemplate in the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent'of the United "States, is: 1. In combination, an element, means for moving said element over a predetermined path of movement with reference to a point,

a rotary switching device having a bank of contacts arranged in groups, each group corresponding to a unit of displacement of said element from said point and each group comprising contacts corresponding to fractionsof aunit of said displacement and ad? ditional contacts intermediate said last men'- tioned contacts, a wiper cooperating with said contacts a circuit and means controlled in response to the pos'ltlon of said element for completing said'circuit when said wiper engages each of said first mentioned con tacts corresponding to fractions of a unit within the instant displacement of said element and for also completingv said circuit through said wiper andv said intermediate contacts in each group corresponding to units wholly within the instant displacement of said element, and signal means responsive to the current in said circuit.

2. In a signaling system, a rotary switch including a group of contacts, a cooper-' in said second group when less than all of the contacts in said second-group are closed.

3. In a signaling system, a rotary switch including a plurality of groups of contacts,

a cooperating wiper and means for moving said wiper into engagement with the contacts of each group of contacts, a, bank of contacts divided into groups corresponding to the groups in said switch, a movable member, means for moving said movable member in accordance with predetermined variations in a variable quantity to close in sequence the contacts of said bank, and inlpnlse transmitti means including said wiper and connections through. the. contacts of said switch and the closed contacts of said bank for transmitting a combination of long and short impulses dependent upon the position of said element.

4. In a signaling system, a rotary switch including a plurality of groups of contacts, a cooperating wiper and means for moving said wiper into engagement with the contacts of each group of contacts, a bank of contacts divided into groups corresponding to the groups in said switch, a movable member, means for moving said movable member in accordance with predetermined variations in aevariable quantity to close in sequence the contacts of said bank, and impulse transmitting means including said wiper and connections through the contacts of said switch and the closed contacts of said bank for transmitting a single relatively long impulse while said wiper is engaging the contacts of each group of contacts in said switch if all of the contacts in the corresponding group said bank are closed and for transmitting a short impulse for each closed contact of the corresponding group in said bank while said wiper is en'- gaging the contacts in agroup of contacts in, said switch if less than all of the contacts in the corresponding group in said bank are closed.

In witness whereof I have hereunto set my hand this 12th day of August, 1929.

' CLYDE E. STEWART. 

